-falign-functions=32, since these two really get hammered on. To make them
faster needs a threadreg or TLS, unless there is a way to tell gcc that a
library-local (pthread__threadmask) variable does not need to be PIC.
preparing to sleep on a mutex are slow in relative terms, so this allows
us to recover from short lock holds without blocking, while not wasting
too much time on longer holds.
kernel to the file server for silly things the file server did,
e.g. attempting to create a file with size VSIZENOTSET. The file
server can handle these as it chooses, but the default action is
for it to throw its hands in the air and sing "goodbye, cruel world,
it's over, walk on by".
Can be used by applications that have their own SIGINT (et al)
handlers and want to exit in a manner that correctly
signals to the parent that the process was terminated by a signal.
See http://www.cons.org/cracauer/sigint.html for more info.
Discussed on tech-userlevel@.
architecture to provide asm versions of the RAS operations.
We do this because relying on the compiler to get the RAS right is not
sensible. (It gets alpha wrong and hppa is suboptimal)
Provide asm RAS ops for hppa.
(A slightly different version) reviewed by Andrew Doran.
- Allow callers to try and release an unheld rwlock. Just return EPERM
as mandated by IEEE Std 1003.1.
- Use pthread__atomic_swap_ptr() to set in the new lock value. At this
point the lock word can't have changed.
pthread__rwlock_wrlock, pthread__rwlock_rdlock:
- Mask out the waiter bits in the lock word before checking to see if
the current thread is about to lock against itself.
the following do not wake other threads early:
pthread_mutex_lock(&mutex);
pthread_cond_broadcast(&cond);
foo = malloc(100); /* takes libc mutexes */
pthread_mutex_unlock(&mutex);
- Eliminate mutexattr_private and just set a bit in ptm_owner if the mutex
is recursive. This forces the slow path to be taken for recursive mutexes.
Overload an unused field in pthread_mutex_t to record whether or not it's
an errorcheck mutex.
- Streamline pthread_mutex_lock / pthread_mutex_unlock a bit more. As a
side effect makes it possible to have assembly stubs for them.
- Update some comments and fix minor bugs. Minor cosmetic changes.
- Replace some spinlocks with mutexes and rwlocks.
- Change the process private semaphores to use mutexes and condition
variables instead of doing the synchronization directly. Spinlocks
are no longer used by the semaphore code.
Instead, make the deferred wakeup list a per-thread array and pass down
the lwpid_t's that way.
- In pthread_cond_wait(), take the mutex before dealing with early wakeup.
In this way there should never be contention on the CV's spinlock if
the app follows POSIX rules (there should only be contention on the
user-provided mutex).
- Add a port of the kernel's rwlocks. The rwlock's spinlock is only taken if
there is contention. This is enabled where atomic ops are available. Right
now that is only i386 and amd64 because I don't have other hardware to
test with. It's trivial to add stubs for other architectures as long as
they have compare-and-swap. When we have proper atomic ops the old rwlock
code can be removed.
- Add a new mutex implementation that's similar to the kernel's mutexes, but
uses compare-and-swap to maintain the waiters list, so no spinlocks are
involved. Same caveats apply as for the rwlocks.
yielding. This is a nasty band-aid but with many threads, looping over
sched_yield() wastes a huge amount of CPU time. It would be nice to have a
way to temporarily disable preemption, but it turns out that's yet another
no-brain concept that has been patented and the patent holder seems to be
suing people lately. Another alternative is probably to have kernel-assisted
spinlocks.
This fix is about the best we can do given the current interfaces. We
could extend the cgetcap(3) interfaces with a function that would return
a character count and handle this in libterm which would provide a more
complete fix and allow a NULL character in a string capability.
leads to loss of precision, leading to rounding into the wrong direction
for the case 0.5-epsilon. use floor() instead.
This also fixes a wrong sign of zero returned with non-default rounding
directions.
Most complex function implementations are from the "c9x-complex" library,
originating from the "cephes" math library, see
http://www.netlib.org/cephes/, from Stephen L. Moshier, incorporated and
redistributed with the NetBSD license by permission of the author.
Error behaviour and other boundary conditions (branch cuts)
need to be looked at.
For namespace sanity, I've done the rename/weak alias procedure to
most of the exported functions which are also used internally.
Didn't do so for sin/cos(f) yet because assembler implementations use
them directly, and renaming functions shared between the main libm
and the machine specific "overlay" might raise binary compatibility
issues.
Chops another ~10% off create/join in a loop on i386.
- Disable low level debugging as this is stable. Improves benchmarks
across the board by a small percentage. Uncontested mutex acquire
and release in a loop becomes about 8% quicker.
- Minor cleanup.
it possible to get the pid, euid and egid of the process at the remote
end at the time it did bind() or connect().
Add a new libc function, getpeereid() to easily get at the euid and egid.
As a consequence, bump libc's minor number.
Document the LOCAL_PEEREID socket option in unix(4).
Based on contribution by Arne H. Juul, minor modifications by myself.
of pending atexit handlers before the structure is reused. This prevents
__cxa_finalize from going into an infinite loop when an atexit handler
register a new atexit handler as in:
#include <stdlib.h>
void two(void) {
}
void one(void) {
atexit(two);
}
int main(void) {
atexit(one);
return 0;
}
hint pointer, but do so in a way that remains compatible with older
pthread libraries. This can be used to wake another thread before the
calling thread goes asleep, saving at least one syscall + involuntary
context switch. This turns out to be a fairly large win on the condvar
benchmarks that I have tried.
detach/join.
- Make mutex acquire spin for a short time, as done with spinlocks.
- Make the number of spins controllable with the env var PTHREAD_NSPINS.
- Reduce the amount of time that libpthread internal spinlocks are held.
- Rely more on the barrier effects of park/unpark to avoid taking spinlocks.
- Simplify the locking around pthreads and the global queues.
- Align per-thread sync data on a 128 byte boundary.
- Offset thread stacks by a small amount to try and reduce cache thrash.
null character outside of the byte region [sbuf, sbuf + len).
1) If the length of the buffer is 0, do not write a null character
at all. Previously, sockaddr_snprintf() may have been able to
overwrite sbuf[-1] if len was 0.
2) If the length of the buffer, len, is greater than 0, then write
the null at sbuf[len - 1]. Previously, sockaddr_snprintf()
wrote the null at buf[len - 1], where `buf' was a "cursor" that
did not necessarily equal `sbuf', the start of the buffer. Now,
sockaddr_snprintf() always writes the null at sbuf[len - 1].
the maximum request size after mount. Calling mount(MNT_GETARGS)
from the file server is currently not kosher, as it vrele()s the
root vnode, potentially causing an inactive, which the file server
cannot handle while it itself is inactive in the kernel (deadlock).
Add an additional call with MNT_GETARGS to retrieve the modified
information instead of relying on the kernel code abusing the mount
interface during mount.
* in addition add/remove, allow enable/disable, which can be used
to control events for descriptors without having to remove all the
data associated with them
* add directsend/receive, which can be used to pass the same buffer
from the caller to read/writeframe and back again
* add flags to enqueue functions and allow urgent buffers to be
processed as the next PDU
- if the process does not exist anymore, return NULL
- if the process has created more lwps retry
XXX[1]: We should fix sysctl_kern_lwp() to return the number of lwps it
needs in oldlenp when ENOMEM. The we can avoid calling sysctl
twice (by starting let's say with always 1 lwp, or 10).
XXX[2]: We should fix kvm_getlwps to never spit errors.
- Silence new lint warnings
o If a long option looks like an ambiguous abbreviation of two or more long
options, but all the possible interpretations would return the same
value, then just return that value without complaining that it's
ambiguous.
o If a long option could be interpreted either as an exact match for one
long option, or as an abbreviation for one or more other long options,
then treat it as the exact match.
These changes align NetBSD's getopt_long(3) with the current behavior of
GNU getopt_long(3), the de facto standard, and FreeBSD's getopt_long(3).
file always after creation to cache the inode number given by the
backend file system. Otherwise we would not find a newly created
node from incore and create another one. In practise this was
pretty well hidden by the kernel name cache.
and destroyed, but not yet reclaimed. This prevents puffs_pn_nodewalk()
from returning stale entries. Make nullfs use this (some file
systems are a bit too happy with recycling inode numbers).
don't create if it is determined that the system in question doesn't need
them. This cleans up build warnings on systems with err.h (HAVE_ERR_H)
for example Mac OS X 10.3.
information, enabled if MULTITHREADED_REFUSE is defined at build
time. This is not enabled by default since libpuffs is not
threadsafe yet.
librefuse is still not threadsafe, but this gets rid of a whole lot of
problems in the meantime.
doesn't obtain the ports, gain and balance related parameters.
Those generally require reading from the hardware and therefore are much
more expensive to obtain. Modify OSS emulation to use the new ioctl
where possible.
This reduces CPU usage of mplayer during mp3 playback with my Thinkpad
from 20% to < 1% and from 50% to 20% during Xvid playback.
Review and comments from jmcneill@
